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Du Y, Zhang Y, Zhang Y, Li T, Wang J, Du Z. Analysis of potential impact factors of corneal biomechanics in myopia. BMC Ophthalmol 2023; 23:143. [PMID: 37024820 PMCID: PMC10077661 DOI: 10.1186/s12886-023-02891-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 03/31/2023] [Indexed: 04/08/2023] Open
Abstract
PURPOSE To investigate potential impact factors associated with corneal biomechanical properties in Chinese myopia and further to investigate quantifying corneal biomechanics in clinical work. METHODS Three hundred fifty-five eyes from 181 healthy myopic subjects with a mean age of 25.1 ± 9.4 were recruited in this study. Each patient carried out a comprehensive ophthalmic examination, including corneal hysteresis(CH), corneal resistance factor(CRF), central corneal thickness(CCT), axial length(AL), intraocular pressure(IOP), spherical equivalence(SE) and corneal curvature (K). CH and CRF were measured with the ocular response analyzer(ORA). To analyze the corneal biomechanical characteristics of myopia patients and their association with other parameters. RESULT The multiple linear regression analysis showed that CH was positively associated with CCT, and corneal curvature (all with P < 0.05) and negatively associated with SE and AL)(all with P < 0.05); CRF was positively correlated with CCT, corneal curvature and IOP(all with P < 0.05), but negatively correlated with SE and AL(all with P < 0.05). The CH and CRF values in children group were both higher than adults group (≥ 18 years old) (P < 0.05), but it attributed to that the CCT of children was thicker than adults. Excluding factor of CCT, there was no significant difference in CH and CRF between children group and adult group. Excluding factor of CCT, there was no significant difference in CH and CRF among different stage of age (age 18-48). CONCLUSION The CCT played the most important role of affecting the CH and CRF. The SE, corneal curvature, AL and IOP had a certain influence on corneal biomechanics. Whether the CH and CRF values of individual patient are normal in clinical work, it should refer to the CH and CRF values corresponding CCT sectional range and SE.
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Affiliation(s)
- Yangrui Du
- Department of Ophthalmology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, People's Republic of China
- Medal Eye Institute, Chongqing, China
| | - Yuqing Zhang
- Department of Ophthalmology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, People's Republic of China
| | - Yu Zhang
- Department of Ophthalmology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, People's Republic of China
- Medal Eye Institute, Chongqing, China
| | - Tao Li
- Department of Ophthalmology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, People's Republic of China
| | - Jie Wang
- Department of Ophthalmology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, People's Republic of China
| | - Zhiyu Du
- Department of Ophthalmology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, People's Republic of China.
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Rasmussen NHH, Dal J, Jensen MH, Kvist AV, van den Bergh J, Hirata RP, Vestergaard P. Impaired postural control in diabetes-a predictor of falls? Arch Osteoporos 2022; 18:6. [PMID: 36482222 DOI: 10.1007/s11657-022-01188-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 11/09/2022] [Indexed: 12/13/2022]
Abstract
New evidence points toward that impaired postural control judged by center of pressure measures during quiet stance is a predictor of falls in people with type 1 and type 2 diabetes-even in occurrence of well-known risk factors for falls. INTRODUCTION/AIM People with type 1 diabetes (T1D) and type 2 diabetes (T2D) are at risk of falling, but the association with impaired postural control is unclear. Therefore, the aim was to investigate postural control by measuring the center of pressure (CoP) during quiet standing and to estimate the prevalence ratio (PR) of falls and the fear of falling among people with diabetes compared to controls. METHODS In a cross-sectional study, participants with T1D (n = 111) and T2D (n = 106) and controls without diabetes (n = 328) were included. Study procedures consisted of handgrip strength (HGS), vibration perception threshold (VPT), orthostatism, visual acuity, and postural control during quiet stance measured by CoPArea (degree of body sway) and CoPVelocity (speed of the body sway) with "eyes open," "eyes closed" in combination with executive function tasks. A history of previous falls and fear of falling was collected by a questionnaire. CoPArea and CoPVelocity measurements were analyzed by using a multiple linear regression model. The PR of falls and the fear of falling were estimated by a Poisson regression model. Age, sex, BMI, previous falls, alcohol use, drug, HGS, VPT, orthostatism, episodes of hypoglycemia, and visual acuity were covariates in multiple adjusted analyses. RESULTS Significantly larger mean CoPArea measures were observed for participants with T1D (p = 0.022) and T2D (0.002), whereas mean CoPVelocity measures were only increased in participants with T2D (p = 0.027) vs. controls. Additionally, T1D and T2D participants had higher PRs for falls (p = 0.044, p = 0.014) and fear of falling (p = 0.006, p < 0.001) in the crude analyses, but the PRs reduced significantly when adjusted for mean CoPArea and mean CoPVelocity, respectively. Furthermore, multiple adjusted PRs were significantly higher than crude the analyses. CONCLUSION: Impaired postural control during quiet stance was seen in T1D and T2D compared with controls even in the occurrence of well-known risk factors. and correlated well with a higher prevalence of falls.
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Affiliation(s)
| | - Jakob Dal
- Department of Endocrinology, Aalborg University Hospital, Aalborg, Denmark
| | - Morten Hasselstrøm Jensen
- Steno Diabetes Center North Denmark, Aalborg University Hospital, Aalborg, Denmark
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Annika Vestergaard Kvist
- Steno Diabetes Center North Denmark, Aalborg University Hospital, Aalborg, Denmark
- Department of Endocrinology and Metabolism, Molecular Endocrinology & Stem Cell Research Unit (KMEB), Odense University Hospital, Odense, Denmark
- University of Southern Denmark, Odense, Denmark
- Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH-Zurich, Zurich, Switzerland
| | - Joop van den Bergh
- School for Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
- Division of Rheumatology, Department of Internal Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands
- Department of Internal Medicine, VieCuri Medical Center, Venlo, The Netherlands
- Faculty of Medicine and Life Sciences, Hasselt University, Hasselt, Belgium
| | - Rogerio Pessoto Hirata
- Faculty of Medicine, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7, 9220, Aalborg East, Denmark
| | - Peter Vestergaard
- Steno Diabetes Center North Denmark, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine and Endocrinology, Aalborg University Hospital, Aalborg, Denmark
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Alzuhairy S. Trans Palpebral Intraocular Pressure Measurement by Diaton Tonometer and Central Corneal Thickness in Eyes before and after Transepithelial Photorefractive Keratectomy of Saudi Patients. Middle East Afr J Ophthalmol 2022; 29:127-131. [PMID: 37408723 PMCID: PMC10319074 DOI: 10.4103/meajo.meajo_156_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 03/14/2023] [Accepted: 03/25/2023] [Indexed: 07/07/2023] Open
Abstract
PURPOSE The influence of central corneal thickness (CCT) on intraocular pressure (IOP) measurement by Diaton is debatable. We present a correlation of CCT to transpalpebral IOP (tpIOP) and its determinants in patients undergoing transepithelial photorefractive keratectomy (TPRK) in Saudi Arabia. METHODS In this cross-sectional study held in 2022, the IOP of patients undergoing TPRK was measured by Diaton tonometer. The CCT was measured before and 1 week after refractive surgery. The correlation coefficient of CCT and IOP and its Pearson P value were estimated. The effects of gender, type of refractive error (RE), and corneal epithelial thickness (CET) on the correlation of IOP to CCT were reviewed. RESULTS We studied 202 eyes in 101 patients (Male: Female, 47:53; age 25.7 ± 5.8 years). The tpIOP was 15.1 ± 2.8 mmHg before, 15.9 ± 2.8 mmHg 1 week after, and 15.7 ± 4.1 mmHg 1 month after TPRK. The CCT was significantly correlated with tpIOP before surgery (Pearson correlation 0.168, P = 0.017) and after tPRK (Pearson correlation 0.246, P < 0.001). Gender (P = 0.96), CET (P = 0.43), and type of RE (P = 0.99) were not significant determinants of correlation between CCT and tpIOP before TPRK. The correlation of tpIOP and CCT was not affected by gender (P = 0.07), CET (P = 0.39), and type of RE (P = 0.13). CONCLUSION CCT should be considered before interpreting tpIOP measured by with Diaton. Diaton could be a useful tool to monitor IOP changes in young patients undergoing refractive surgery.
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Affiliation(s)
- Sultan Alzuhairy
- Department of Ophthalmology, College of Medicine, Qassim University, Buraidah, Saudi Arabia
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Hashemian SJ, Hashemian SM, Karimian F, Hadavandkhani A, Jafari ME, Hashemian MS, Hadi Y, Semnani FN. Ocular Biometric Values and Prevalence of Corneal Astigmatism in Patients Candidate for Cataract Surgery. J Curr Ophthalmol 2022; 34:56-59. [PMID: 35620375 PMCID: PMC9128422 DOI: 10.4103/joco.joco_33_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 08/21/2021] [Accepted: 08/24/2021] [Indexed: 11/17/2022] Open
Abstract
Purpose To analyze the biometric values and the prevalence of corneal astigmatism in cataract surgery candidates. Methods This is a prospective study. Ocular biometric values and corneal keratometric astigmatism were measured by optical low-coherence reflectometry (Lenstar LS 900) before surgery in patients who were candidates for cataract extraction surgery. Descriptive measurements of biometric dimensions and keratometric cylinder data and their correlations with sex and age were evaluated. Results Ocular biometric and keratometric values from 2084 eyes of 2084 patients (mean age 66.43, range 19-95 years) were analyzed. The mean values were as follows: corneal astigmatism 0.89 diopter (D), mean corneal keratometry 44.29 D, central corneal thickness 534 μ, internal anterior chamber depth (ACD) 3.11 mm, lens thickness 4.50 mm, and axial length 23.35 mm. Corneal astigmatism was <1.25 D in 1660 (79.5%) of eyes. Astigmatism was with-the-rule in 976 (46.8%) of eyes, against-the-rule (ATR) in 702 (33.7%), and oblique in 406 (19.5%). Analysis of corneal astigmatism revealed a change toward "ATR" with age which was not statistically significant. The ACD was correlated with age. The amount of corneal astigmatism had no correlation with age and sex. Conclusion Corneal astigmatism was higher than 1.25 D in about 21% of cataract surgery candidates with slight differences between the various age ranges and had no correlation with age and sex.
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Affiliation(s)
- Seyed Javad Hashemian
- Eye Research Center, Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | | | - Farid Karimian
- Labbafinejad Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ali Hadavandkhani
- Eye Research Center, Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | | | - Mahsa Sadat Hashemian
- Eye Research Center, Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Yasaman Hadi
- Eye Research Center, Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Nadjafi Semnani
- Eye Research Center, Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
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Sun MG, Son T, Crutison J, Guaiquil V, Lin S, Nammari L, Klatt D, Yao X, Rosenblatt MI, Royston TJ. Optical coherence elastography for assessing the influence of intraocular pressure on elastic wave dispersion in the cornea. J Mech Behav Biomed Mater 2022; 128:105100. [PMID: 35121423 PMCID: PMC8904295 DOI: 10.1016/j.jmbbm.2022.105100] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 01/17/2022] [Accepted: 01/21/2022] [Indexed: 10/19/2022]
Abstract
The cornea is a highly specialized organ that relies on its mechanical stiffness to maintain its aspheric geometry and refractive power, and corneal diseases such as keratoconus have been linked to abnormal tissue stiffness and biomechanics. Dynamic optical coherence elastography (OCE) is a clinically promising non-contact and non-destructive imaging technique that can provide measurements of corneal tissue stiffness directly in vivo. The method relies on the concepts of elastography where shear waves are generated and imaged within a tissue to obtain mechanical properties such as tissue stiffness. The accuracy of OCE-based measurements is ultimately dependent on the mathematical theories used to model wave behavior in the tissue of interest. In the cornea, elastic waves propagate as guided wave modes which are highly dispersive and can be mathematically complex to model. While recent groups have developed detailed theories for estimating corneal tissue properties from guided wave behavior, the effects of intraocular pressure (IOP)-induced prestress have not yet been considered. It is known that prestress alone can strongly influence wave behavior, in addition to the associated non-linear changes in tissue properties. This present study shows that failure to account for the effects of prestress may result in overestimations of the corneal shear moduli, particularly at high IOPs. We first examined the potential effects of IOP and IOP-induced prestress using a combination of approximate mathematical theories describing wave behavior in thin plates with observations made from data published in the OCE literature. Through wave dispersion analysis, we deduce that IOP introduces a tensile hoop stress and may also influence an elastic foundational effect that were observable in the low-frequency components of the dispersion curves. These effects were incorporated into recently developed models of wave behavior in nearly incompressible, transversely isotropic (NITI) materials. Fitting of the modified NITI model with ex vivo porcine corneal data demonstrated that incorporation of the effects of IOP resulted in reduced estimates of corneal shear moduli. We believe this demonstrates that overestimation of corneal stiffness occurs if IOP is not taken into consideration. Our work may be helpful in separating inherent corneal stiffness properties that are independent of IOP; changes in these properties and in IOP are distinct, clinically relevant issues that affect the cornea health.
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